The present invention relates to an optical method used to monitor the processing of a starch-containing material.
Starch is a naturally-occurring material obtained from various plants such as potato, and tapioca, and cereal grains such as corn, rice, wheat, barley, and the like. Starches are polysaccharide compounds which on hydrolysis produce sugars. As used herein, starch can include a mixture of linear components generally referred to as amylose, and branched components generally referred to as amylopectin. Amylose generally has a molecular weight of several hundred thousand, while amylopectin generally has a molecular weight in the order of several million. The processing of starches containing 0 to 100% amylose or 0 to 100% amylopectin can be monitored using Applicants"" optical method.
As used herein, starch should also be understood to include starches with a high amylopectin content sometimes called waxy starches, as well as chemically and physically modified starches, such as for example starches whose acid values have been reduced, starches in which the type and concentration of cations associated with the phosphate groups have been modified, ethoxylated starches, starch acetates, cationic starches, oxidated starches and cross-linked starches.
Starch forms a granule located with the endosperm of many plants, including the cereal grains. Cereal grains typically contain between about 60 weight percent to about 80 weight percent starch. Between about 0 weight percent and about 100 weight percent of this starch may exist in a crystalline state. Generally, between about 50 weight percent and about 100 weight percent of the starch in cereal grains exists in a crystalline domains.
When these starch granules are heated in the presence of water, the granules swell and the microstructure of the constituent starch becomes less crystalline. It is sometimes said that the starch is becoming destructurized. The water solubility of starch increases as the degree of crystallinity decreases. This process is sometimes referred to as starch gelatinization.
Most cereal grains are processed to expose and/or gelatinize starch. The microstructure of such gelatinized starch is less dense, and is more completely and more readily digested by mammals and bacteria. Processing methods include but are not limited to: grinding, dry rolling, steam rolling, pelleting, steam flaking, pressure flaking, popping, micronizing, exploding, extruding, roasting, high-moisture harvesting, and reconstitution.
Certain animals, including beef cattle, digest starch in various portions of the digestive tract. The degree of starch gelatinization in a cereal grain determines the amount of starch that can be digested in the rumen, or fore stomach, of a cow. Too little digestion of starch in the rumen results in inefficient use of the feed-stuff. On the other hand, too rapid digestion in the rumen may lead to digestive disorders. Therefore, the processing of starch-containing materials is monitored in order to ascertain, for example, the level of starch gelatinization
A number of analytical protocols exist which are used to monitor the gelatinization of starch in a starch-containing foodstuff. These quality control protocols currently include, for example: flake weight measurement, microscopic examination (Schoch and Maywald, xe2x80x9cMicroscopic Examination of Modified Starches,xe2x80x9d Anal. Chem. 28:382, 1965), enzymatic analysis (Sung, An-Chein, xe2x80x9cEnzymatic Evaluation of Changes in Processed Grains, Feedstuffs 19:22., 1960), and fermentation analyses (Croka and Wagner, xe2x80x9cMicronized Sorghum Grain: Influence of In Vitro Digestibility, In Vitro Gas Production and Gelatinization, Journal of Animal Science, 40:931, 1975; Trei et. al., xe2x80x9cEffect of Grain Processing on In Vitro Gas Production, J. Anim. Sci. 30:825., 1970).
These analytical procedures, however, suffer from certain disadvantages. For example, several of these techniques require pretreatment of the sample prior to analysis or are subject to operator bias. Microscopic examination requires subjective analysis by trained persons. Enzymatic analyses and fermentation analyses require use of laboratory equipment and trained personnel.
What is required is a reliable, easily performed, and low cost analytical method to estimate the degree of starch availability during or after the processing of starch-containing food-stuffs.
Applicants"" invention includes a method to measure certain optical characteristics of a starch-containing material during and/or after processing in order to estimate the degree of starch availability. According to Applicants"" method, samples of the starch-containing material are obtained during and/or after processing.
Light having a defined frequency and intensity is directed onto at least one surface of the test sample from one or more light sources. The light reflected from the sample is received through one or a plurality of light receivers. Certain optical characteristics of the reflected light are then measured. These measured optical characteristics include reflected surface color spectrum, reflected bulk material color spectrum, gloss translucency, fluorescence, and surface texture or a combination of the above. Sample attributes such as sample flake weight and starch availability can then be estimated by comparing the measured optical characteristics of the sample with known calibration curves.
When using wet processing methods, the optical properties measured relate to starch gelatinization. When using dry processing methods, the optical properties measured relate to starch exposure. In either event, the optical properties measured can be used to estimate the samples"" flake weight and/or starch availability for wet processing or fineness of grind for dry processing.
In another embodiment, the calculated processing parameters, such as flake weight and/or starch availability, are displayed on a visual display device. In another embodiment, an oral representation of those calculated processing parameters is generated and announced.